Underground Storage Tanks Still Causing Widespread Contamination

Piping, spill/overfill and dispenser leaks top the list of items that are suspected as the source for much of the new contamination being discovered throughout the country according to EPA.

Preliminary information from an EPA UST System Evaluation Report looked at information from 300 sites with known leakage and at autopsies of 50 other sites to determine the cause and source of leaks. Although the report does not contain enough data to draw definitive conclusions, it does indicate trends related to equipment, system and operator performance, according to EPA's Office of Underground Storage Tanks.

The EPA has identified piping, spill/overfill and dispensers as the sources for the majority of the leaks, with human error indicated as the principal cause. In addition, spill/overfill, mechanical failure and physical damage were given as causes for leaks. The report found that releases were not often detected by leak detection devices but rather were discovered most frequently either visually or by smell.

Most of the systems investigated were single-wall systems, which can easily allow releases directly into the environment. Currently, three-quarters of the 704,717 active USTs in the United States are single-wall piping.

Publications related to underground storage tanks are available online.

Updated: Feb. 25, 2004